"Increasing ocean stratification over the past half-century
Guancheng Li, Lijing Cheng, Jiang Zhu, Kevin E. Trenberth, Michael E. Mann & John P. Abraham "
"Seawater generally forms stratified layers with lighter waters near the surface and denser waters at greater depth. This stable configuration acts as a barrier to water mixing that impacts the efficiency of vertical exchanges of heat, carbon, oxygen and other constituents. "
"We find that stratification globally has increased by a substantial 5.3% [5.0%, 5.8%] in recent decades (1960–2018) (the confidence interval is 5–95%); a rate of 0.90% per decade. Most of the increase (~71%) occurred in the upper 200 m of the ocean and resulted largely (>90%) from temperature changes, although salinity changes play an important role locally."
https://www.nature.com/articles/s41558-020-00918-2Dated 28 September
So now Trenberth's heat hiding in the "deep ocean" is now not; it is mostly in the top 200m The stratification prevents the mixing to the deep ocean.
But then -
"New research reveals temperatures in the deep sea fluctuate more than scientists previously thought and a warming trend is now detectable at the bottom of the ocean."
"In a new study in AGU’s journal Geophysical Research Letters, researchers analyzed a decade of hourly temperature recordings from moorings anchored at four depths in the Atlantic Ocean’s Argentine Basin off the coast of Uruguay. The depths represent a range around the average ocean depth of 3,682 meters (12,080 feet), with the shallowest at 1,360 meters (4,460 feet) and the deepest at 4,757 meters (15,600 feet).
They found all sites exhibited a warming trend of 0.02 to 0.04 degrees Celsius per decade between 2009 and 2019 – a significant warming trend in the deep sea where temperature fluctuations are typically measured in thousandths of a degree. According to the study authors, this increase is consistent with warming trends in the shallow ocean associated with anthropogenic climate change, but more research is needed to understand what is driving rising temperatures in the deep ocean."
https://news.agu.org/press-release/the-deep-sea-is-slowly-warming/Dated 13 October
So in a fortnight it is not in the deep ocean, but it is.
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089093And they know this is widespread from exactly four sites.
And of course those dratted global average ocean temperatures back to 1880 with an accuracy of .01C? Farcical, the same as the global average land temperatures going back that far. And of course even now. Supposedly accurate to within 1/100th of a degree C.
September Ranks and Records
September Anomaly Rank
(out of 141 years) Records
°C °F Year(s) °C °F
Global
Land +1.49 ± 0.29 +2.68 ± 0.52 Warmest 1st 2020 +1.49 +2.68
Coolest 141st 1884 -0.78 -1.40
Ocean +0.77 ± 0.14 +1.39 ± 0.25 Warmest 4th 2015 +0.83 +1.49
Coolest 138th 1903,
1904,
1908 -0.47 -0.85
Land and Ocean+0.97 ± 0.16 +1.75 ± 0.29 Warmest 1st 2020 +0.97 +1.75
Coolest 141st 1912 -0.53 -0.95
https://www.ncdc.noaa.gov/sotc/global/202009